Growth and characterization of CaCu₃Ru₄O₁₂ single crystal

High-quality single crystals of A-site ordered perovskite oxides CaCu₃Ru₄O₁₂ were synthesized by flux method with CuO serving as a flux. The typical size of these single crystals was around 1× 1× 1 mm³ and the lattice constant was determined to be 7.430± 0.0009 Å by using x-ray single crystal diffraction. The surfaces of the samples were identified to be (100) surface. The high quality of the single crystal samples was confirmed by the rocking curve data which have a full width at half maximum of approximately 0.02 degree. The x-ray photoelectron spectroscopy measurement was performed and the temperature-dependent specific heat, magnetic susceptibility, and electric resistivity were measured along the 100 direction of the single crystals. All these measurements showed that the physical properties of CaCu₃Ru₄O₁₂ single crystals are similar to that of polycrystals. However, the single crystals have a lower Curie susceptibility tail and a smaller residual resistivity than polycrystals, which indicates that the amount of paramagnetic impurities can be controlled by tuning the number of defects in CaCu₃Ru₄O₁₂ samples.